From:Dave Hennessey
Subject:RE: RE: RE: Bosch points - where to get them Date:Wed Aug 29 12:41:21 2018
Response to:6924
Anyone got a source for points for the KJ's Bosch FF4AR
magneto ?

Thanks to everyone who replied here or emailed me with possible sources.

I found the points ($20) and an interrupter arm ($25) at Mark's Magnetos in Connecticut 860-537-0376 (as suggested by John Yushkevitch).

Mark's is the place to go! They said they have a bunch of magnetos running in the Cannonball (Mark Hill is a customer).

Also, if you need a Bosch armature rewound, Mark's Magnetos does it. My armature crapped out a few years ago, and Dave Panella came to the rescue with an armature that had been rewound by Jack Hurt out in California. Mark's said that Mr. Hurt is slowing down these days, and they are getting more rewinding business.

My magneto saga:

Two years ago, I was driving around the countryside and stopped at a little store to get gas and a Coke. When I finished my Coke, the bike wouldn't start. I only had a screwdriver and pliers, but that was enough to figure out that the rubbing block had fallen off the interrupter arm. Later examination showed that the little pins holding the rubbing block to the arm had worn through the metal in the arm. Why? I have no idea.

Then I saw that the points screws didn't have any "points" - the tungsten (or platinum) contacts were missing from both sides. The points screws had a convex on one, and a concave on the other, where the contacts were soldered or spot-welded or whatever to the screws.

I have no idea how long they were like that - maybe years? The bike started and ran fine until the rubbing block broke off. Heck, maybe those "contacts" are optional!!!

I happened to have a junk FU4BR that I picked up for cheap - in case I ever needed points. So I swapped in the points from the junker, which did have contacts on them.

Fast-forward to last week. I went from my house to the nearest gas station, about 2 mniles away. After filling up, the bike wouldn't start. Out in the blazing hot sun with only a screwdriver and pliers.

I couldn't tell exactly what, but the points looked odd - like they wouldn't close. Later examination showed that the moving point had lost 7/8 of the circle of tungsten, and the the remaining 1/8 was burned and not passing electricity - basically holding the points open.

No more junk mags to steal points from, so I just filed the remaining 1/8 down to flat, set the gap, and guess what - it starts and runs perfectly.

Now I've got points coming in from Marks in a few days, and can get the mag back to proper working configuration.

Somewhere I read that a fix would be to find a TIG welder electrode (tungsten) of the proper diameter, part off a slice of the proper thickness on a lathe, and silver solder them to the steel screws. Easier to just buy them from Marks.

Another source is and a few other pages in that area. Prices are a little higher, since the dollar-euro isn't favorable, VAT tax, shipping from Germany, but they seem to have a lot of good stuff.

This Saturday will be September 1 - the start of the automotive model year, and my KJ will be turning a spritely 89-years-old. I'm planning a nice long birthday ride!